Method and system for providing hearing assistance to a user

Abstract

Method for providing hearing assistance to a user by capturing audio signals with a microphone arrangement of a transmission unit; analyzing, by a voice activity detector of the transmission unit, the captured audio signals to judge whether a voice is present close to the microphone arrangement or not, analyzing, by a noise level estimator, the captured audio signals to estimate a surrounding noise level, processing the captured audio signals and transmitting, by a transceiver of the transmission unit, the processed audio signals via a wireless link to a receiver unit, and stimulating the user's hearing, by stimulating means at or in at least one user ear, according to the received audio signals, wherein the audio signals are processed via the wireless link by setting the gain applied to the audio signals according to the close voice/no close voice judgment of the voice activity detector and the estimated surrounding noise level.

What is claimed is: 
     
       1. A method for providing hearing assistance to a user, comprising:
 capturing audio signals by a microphone arrangement ( 17 ) of a transmission unit ( 10 ,  110 ); 
 analyzing, with a voice activity detector ( 24 ) of the transmission unit, the captured audio signals in order to judge whether a voice is present close to the microphone arrangement or not; 
 analyzing, by a noise level estimator ( 25 ), the captured audio signals in order to estimate a surrounding noise level; 
 processing the captured audio signals and transmitting, with a transceiver ( 28 ) of the transmission unit, the processed audio signals via a wireless link ( 12 ) to a receiver unit ( 14 ,  114 ,  214 ); and 
 stimulating the user's hearing with stimulating means ( 16 ,  64 ,  82 ,  182 ) worn at or in at least one of the user's ears in accordance with the transmitted processed audio signals received by the receiver unit; 
 wherein the audio signals are processed prior to and/or after transmission via the wireless link by applying a gain to the audio signals according to close voice/not close voice judgment of the voice activity detector and the surrounding noise level estimated, 
 wherein said gain is set to a first gain value (g 1 ) during times when the presence of close voice is judged, wherein said gain is reduced from the first gain value by an attenuation value (a) to a second gain value (g 2 ) when a change from close voice to not close voice is judged, and 
 wherein the attenuation value is selected as a function of the surrounding noise level estimated in such a manner that the attenuation value increases as the surrounding noise level estimated increases. 
 
     
     
       2. The method of  claim 1 , wherein the audio signals received by the receiver unit ( 14 ,  114 ) are processed, by a gain control unit ( 62 ,  74 ,  120 ), by applying said gain to the received audio signals. 
     
     
       3. The method of  claim 1 , wherein the captured audio signals are processed, prior to transmission, by a gain control unit ( 20 B) of the transmission unit ( 110 ), by applying said gain to the captured audio signals. 
     
     
       4. The method of  claim 1 , wherein said gain is increased from the second gain value (g 2 ) by the attenuation value (a) to the first gain value (g 1 ) when a change from no close voice to close voice is judged. 
     
     
       5. The method of  claim 2 , wherein the voice activity detector ( 24 ) generates a close voice judgement value, and wherein the noise level estimator ( 25 ) generates a surrounding noise level estimation value. 
     
     
       6. The method of  claim 5 , wherein the attenuation value (a) is determined in the transmission unit ( 10 ) from the close voice judgement value and the surrounding noise level estimation value, and wherein the attenuation value or a corresponding command for the gain control unit ( 62 ,  74 ,  120 ) is transmitted to the receiver unit ( 14 ,  114 ). 
     
     
       7. The method of  claim 5 , wherein the noise level estimator ( 25 ) is part of the transmission unit ( 10 ), and wherein audio signals captured by the microphone arrangement ( 17 ) are supplied as input to the noise level estimator. 
     
     
       8. The method of  claim 7 , wherein the close voice judgement value and the surrounding noise level estimation value are transmitted via the digital wireless link ( 12 ) to the receiver unit ( 14 ,  114 ) for selecting the attenuation value (a). 
     
     
       9. The method of  claim 1 , wherein the attenuation value (a) is set to a minimum attenuation value (a min ) when the estimated surrounding noise level is at or below a first threshold value (l 1 ). 
     
     
       10. The method of  claim 9 , wherein the first threshold value (l 1 ) is not more than 66 dBA. 
     
     
       11. The method  claim 9 , wherein the attenuation value (a) is set to a maximum attenuation value (a max ) when the estimated surrounding noise level is above or at a second threshold value (l 2 ). 
     
     
       12. The method of  claim 11 , wherein the maximum attenuation value (a max ) is at least 10 dB. 
     
     
       13. The method of  claim 11 , wherein the second threshold value (l 2 ) is at least 70 dBA. 
     
     
       14. The method of  claim 11 , wherein the attenuation value (a) is selected to increase linearly with a first slope within a first range of the estimated surrounding noise level with increasing estimated surrounding noise level. 
     
     
       15. The method of  claim 14 , wherein the attenuation value (a) is set to a minimum attenuation value (a min ) when the estimated surrounding noise level is at or below a first threshold value (l 1 ), wherein the first range is limited by the first threshold value (l 1 ) and the second threshold value (l 2 ), respectively. 
     
     
       16. The method of  claim 9 , wherein the minimum attenuation value (a min ) is not more than 6 dB. 
     
     
       17. The method of  claim 1 , wherein the first gain value (g 1 ) is set as a function of the estimated surrounding noise level. 
     
     
       18. The method of  claim 17 , wherein the first gain value (g 1 ) is selected to increase with increasing estimated surrounding noise level. 
     
     
       19. The method of  claim 18 , wherein the first gain value (g 1 ) is selected to increase linearly with a second slope within a second range of the estimated surrounding noise level with increasing estimated surrounding noise level. 
     
     
       20. The method of  claim 14 , wherein the first gain value (g 1 ) is selected to increase linearly with a second slope within a second range of the estimated surrounding noise level with increasing estimated surrounding noise level, wherein the first gain value (g 1 ) has a lower constant value (g min ) when the estimated surrounding noise level is below or at the lower limit of said second range and has an upper constant value (g max ) when the estimated surrounding noise level is above or at the upper limit (l 2 ) of said second range. 
     
     
       21. The method of  claim 19 , wherein the first slope is smaller than the second slope. 
     
     
       22. The method of  claim 13 , wherein the first gain value (g 1 ) is selected to increase with increasing estimated surrounding noise level, and wherein the first range and the second range are identical. 
     
     
       23. The method of  claim 16 , wherein during times when no presence of close speech is judged the second gain value (g 3 ) is adjusted, upon a change in the estimated surrounding noise level, to the new estimated surrounding noise level according to a function which varies less strongly with the estimated surrounding noise level than the function of the first gain value (g 1 ) and the function of the attenuation value (a). 
     
     
       24. The method of  claim 1 , wherein the surrounding noise level estimation is performed only if it has been judged that there is no close voice captured by the microphone arrangement ( 17 ). 
     
     
       25. The method of  claim 1 , wherein the gain control unit ( 20 B,  62 ,  74 ,  120 ) reduces the gain progressively from the first value (g 1 ) to the second value (g 2 ) during a given release time period when a change from close voice to no close voice is judged. 
     
     
       26. The method of  claim 15 , wherein the release time period is from 100 ms to 10 seconds. 
     
     
       27. The method of  claim 1 , wherein the gain control unit ( 20 B,  62 ,  74 ,  120 ) keeps the gain at the first gain value (g 1 ) for a given hold-on time period when a change from close voice to no close voice is judged, prior to progressively reducing the gain from the first gain value to the second gain value (g 2 ) during a release time period. 
     
     
       28. The method of  claim 17 , wherein the hold-on time period is from 100 ms to 10 seconds. 
     
     
       29. The method of  claim 1 , wherein the gain control unit ( 20 B,  62 ,  74 ) increases the gain within an attack time period from the second gain value (g 2 ) to the first gain value (g 1 ) when a change from no close voice to close voice is judged. 
     
     
       30. The method of  claim 29 , wherein the attack time period is from 0.5 ms to 10 ms. 
     
     
       31. The method of  claim 1 , wherein the microphone arrangement ( 17 ) comprises at least two spaced apart microphones ( 17 A,  17 B), wherein for judging whether a voice is present close to the microphone arrangement, the total energy contained in the voice spectrum of the audio signals captured at at least one of the microphones is estimated, and wherein the value of the direction of arrival of the captured audio signals is estimated by comparing the audio signals captured by at least two of the spaced apart microphones. 
     
     
       32. The method of  claim 1 , wherein the transceiver ( 28 ) is a digital transceiver and wherein the wireless link ( 12 ) is a digitally modulated link. 
     
     
       33. The method of  claim 1 , wherein said first gain value is applied in the receiver unit and said attenuation value is applied in the transmission unit. 
     
     
       34. A system for providing hearing assistance to a user, comprising:
 a receiver unit ( 14 ,  114 ): 
 a transmission unit ( 10 ) comprising 
 a microphone arrangement ( 17 ) for capturing audio signals, 
 a voice activity detector ( 24 ) for analyzing the captured audio signals in order to judge whether a voice is present close to the microphone arrangement, 
 an audio signal processing unit ( 20 ) for processing the captured audio signals, 
 a transceiver ( 28 ) for transmitting the processed audio signals via a wireless link ( 12 ) to the receiver unit; 
 the system comprising a noise level estimator ( 25 ) for analyzing captured audio signals in order to estimate a surrounding noise level, 
 the system further comprising 
 a gain control unit ( 62 ,  74 ,  120 ), and 
 means ( 62 ,  74 ) for processing the received audio signals by setting, by said gain control unit, the gain applied to the audio signals according to the close voice judgment and the estimated surrounding noise level; and 
 means ( 16 ,  64 ,  82 ,  120 ) to be worn at or in at least one of the user's ears for stimulating the user's hearing according to the audio signals processed by said means for processing the received audio signals; 
 wherein said gain is set to a first gain value (g 1 ) as a function of the surrounding noise level estimation during times when the presence of close voice is judged, wherein said gain is reduced from the first gain value by an attenuation value (a) to a second gain value (g 2 ) when a change from close voice to no close voice is judged, and wherein the attenuation value is selected as a function of the estimated surrounding noise level in such a manner that the attenuation value increases with increasing estimated surrounding noise level. 
 
     
     
       35. The system of one of  claim 34 , wherein the stimulating means ( 82 ) is part of the receiver unit ( 14 ,  214 ) or is directly connected thereto. 
     
     
       36. The system of one of  claim 34 , wherein the receiver unit ( 14 ,  114 ,  214 ) is part of or connected to a hearing instrument ( 16 ,  64 ) comprising the stimulating means ( 182 ). 
     
     
       37. The system of  claim 36 , wherein the gain control unit ( 120 ) forms part of the hearing instrument ( 64 ). 
     
     
       38. The system of  claim 36 , wherein the gain control unit ( 62 ) forms part of the receiver unit ( 14 ). 
     
     
       39. The system of  claim 34 , wherein the noise level estimator ( 25 ) is part of the transmission unit ( 10 ,  110 ). 
     
     
       40. A system for providing hearing assistance to a user, comprising:
 a receiver unit ( 214 ); 
 a transmission unit ( 110 ) comprising 
 a microphone arrangement ( 17 ) for capturing audio signals, 
 a voice activity detector ( 24 ) for analyzing the captured audio signals in order to judge whether a voice is present close to the microphone arrangement, 
 an audio signal processing unit ( 20 ) for processing the captured audio signals, the audio signal processing unit including a gain control unit ( 20 B) 
 a transceiver ( 28 ) for transmitting the processed audio signals via a wireless link ( 12 ) to the receiver unit; 
 the system comprising a noise level estimator ( 25 ) for analyzing captured audio signals in order to estimate a surrounding noise level, 
 means ( 16 ,  64 ,  82 ) to be worn at or in at least one of the user's ears for stimulating the user's hearing according to the audio signals received by said receiver unit; 
 wherein said gain control unit is adapted set the gain applied to the captured audio signal to a first gain value (g 1 ) as a function of the surrounding noise level estimation during times when the presence of close voice is judged, wherein said gain is reduced from the first gain value by an attenuation value (a) to a second gain value (g 2 ) when a change from close voice to no close voice is judged, and wherein the attenuation value is selected as a function of the estimated surrounding noise level in such a manner that the attenuation value increases with increasing estimated surrounding noise level. 
 
     
     
       41. The system of one of  claim 40 , wherein the stimulating means ( 82 ) is part of the receiver unit ( 14 ,  214 ) or is directly connected thereto. 
     
     
       42. The system of one of  claim 40 , wherein the receiver unit ( 14 ,  114 ,  214 ) is part of or connected to a hearing instrument ( 16 ,  64 ) comprising the stimulating means ( 182 ). 
     
     
       43. The system of  claim 42 , wherein the gain control unit ( 120 ) forms part of the hearing instrument ( 64 ). 
     
     
       44. The system of  claim 42 , wherein the gain control unit ( 62 ) forms part of the receiver unit ( 14 ). 
     
     
       45. The system of  claim 40 , wherein the noise level estimator ( 25 ) is part of the transmission unit ( 10 ,  110 ).